In a digital video recording (DVR) environment, DVR software records multimedia programs for later replay or archiving (as described herein, digital video recording may include audio and other information, such as program metadata). Ideally, each recording of a program is stored in an independent digital file. For instance, a recording of the “The West Wing” television program is ideally stored in its own file on a hard disk. When multiple programs are recorded back-to-back on the same channel, each program from the multimedia stream is stored in a separate digital file despite the fact that the recording appears continuous from the perspective of a human user.
DVRs and personal video recorders (PVRs) sometimes add extra recording time before and after a program being recorded (pre-padding and post-padding) to ensure that the entire program is recorded. This automatic padding before and after a program is usually referred to as “soft” padding because it is added only if it would not interfere with the recording of another program. This pre-padding and post-padding can prevent lost program content due to inaccurate broadcaster scheduling, an inaccurate clock, and other irregularities. For instance, if the policy of the DVR software is to append five minutes of pre and post padding to a program that does not immediately follow or precede another program being recorded on the same tuner, then the DVR records for an additional ten minutes over the length of the program, five minutes before and five minutes after. Some DVRs also allow the user to select “hard” padding, in which a selected time period of pre and/or post padding can be appended to a recorded program, sometimes even regardless of programs to be recorded immediately preceding or following the subject program. This hard padding can give rise to prioritization of adjacent programs to be recorded and subsequent truncation of the programs with lower priority.
Usually, when two programs are scheduled to be recorded back-to-back using the same tuner, the DVR does not intentionally apply any padding but instead makes a “judgement call” regarding the point in time at which the first of the adjacent programs ends and its digital storage file is closed, and the subsequent program begins and its digital storage file is opened. The discernment of when a first program ends and the next program begins is usually satisfactory since it is based on the broadcaster's scheduled time listings. Not infrequently, however, the DVR places the demarcation between adjacently recorded programs at the wrong place. This can be due to inaccuracies in the schedule listings information, clock inaccuracies, or unpredictability of program length, for example, in the case of a live sporting event that extends past an anticipated finish time. When the temporal dividing line between programs is applied inaccurately, an unintentional padding occurs. If the temporal division between programs is made too early, then the ending of the first program is truncated from the digital file storing the first program, and this ending of the first program becomes unintended pre-padding for the following program. If the temporal division between programs is made too late, then the beginning of the subsequent program is truncated from the digital file storing the subsequent program and becomes unintended post-padding for the first program. In either case, the truncated portion of a program is generally lost to DVR tracking, unless the sequence of program recording is manually reconstructed by the user and the unintentional pre or post padding is located and played back to retrieve the lost part of the program.